JP3320496B2 - Manufacturing method of ceramic or metal powder sintered body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a ceramic or metal powder sintered body.

[0002]

2. Description of the Related Art Conventionally, a ceramic or metal powder sintered body has been manufactured by molding a kneaded body of ceramic or metal powder and an organic binder to obtain a molded body, and then forming the molded body on a fire-resistant base plate of alumina or the like. It is generally known to mount a body and sinter it in a high-temperature furnace such as an electric furnace. Further, as disclosed in Japanese Patent Application Laid-Open No. 57-200271, in order to uniformly transmit the sintering energy from the entire outer periphery of the compact during sintering, the compact is placed in a refractory powder such as alumina powder. A technique of burying and sintering is known, and this technique has been used to alleviate deformation and sintering cracks of a compact due to a difference in absorption efficiency of sintering energy absorbed by the compact.

[0003]

However, in the former of these methods, the compact can be stably mounted on the fire-resistant base plate, and there is almost no deformation occurring during degreasing and sintering. If there is no bearing surface, it will not be feasible, or it will be necessary to create a special jig for refractory material, and it will be necessary to perform post-processing such as sizing because the convex parts will be deformed by their own weight. There is a problem that the cost can be increased. In the latter case, the refractory powder body such as alumina may adhere to the molded body by sintering, so that post-treatment such as polishing is required, the process becomes longer, and the refractory powder body becomes resistant and uniformly shrinks. Therefore, there is a problem that deformation due to a difference in shrinkage occurs.

Accordingly, the present invention has been made in view of the above problems, and suppresses deformation due to differential shrinkage and deformation due to its own weight, does not require post-processing such as sizing and polishing, and has a bearing surface. An object of the present invention is to provide a method for producing a ceramic or metal powder sintered body that can easily be sintered even with a molded body having no shape.

[0005]

SUMMARY OF THE INVENTION The present invention is a method for producing a ceramic or metal powder sintered body for solving the above-mentioned problems. In the production method, a step of injection-molding a kneaded body of ceramics or metal powder and an organic binder as an injection molding material to obtain a molded body as a product part, and a kneaded body of the same material as the molded body or an organic material Injection molding a kneaded body with a large amount of binder as an injection molding material, a step of obtaining a jig to be fitted and combined with the molded body, and preventing a contact between the molded body and the jig at a fitting contact portion between the two. And a step of degrease and sintering the molded body and the jig fitted and combined via the film. According to a second aspect of the present invention, in the method for producing a ceramic or metal powder sintered body according to the first aspect, the step of applying the film includes a step of applying physicochemical stability to a fitting contact portion between the molded body and the jig. It is characterized by performing by applying or vapor-depositing a suitable ceramic. A description will be given based on FIGS. 1 to 5 exemplifying a conceptual diagram of the present invention. The manufacturing method exemplified by the present invention comprises a step of injection-molding a kneaded body of ceramics or metal powder and an organic binder as an injection molding material to obtain a plurality of injection-molded articles, and a step of contacting them with the surface of the injection-molded article. It comprises a step of forming a film to be prevented, a step of combining the molded bodies, a step of degrease the injection molded body, and a step of sintering the degreased body.

[0006] A molded body 1a which is a product part in an injection molding process
And a jig 2a which is formed of the same material (with any mixing ratio), is fitted to the molded body 1a, and is stably maintained on a refractory base plate used at the time of degreasing and sintering. . After the degreasing step, the molded body 1a and the jig 2a, which are product parts, are fitted and combined, and at this fitting, the molded body 1a
A film is formed on the fitting contact portion of the jig 2a and the jig 2a to prevent them from coming into contact with each other. Specifically, the contact portion is made of Al ₂
O ₃ (alumina), SiO ₂ , c-BN, SiO, Si
_{3 N 4, h-BN,} TiO 2 -Al 2 O 3, Al 2 O 3
-ZrO ₂ or the like, a ceramic coating 3 applied by coating or depositing a physicochemically stable ceramics, thereafter fitted. Thereafter, through a degreasing and sintering process, the obtained sintered body is separated into a product 1 and a jig 2 to obtain a desired product.

[0007]

In the above construction, ceramics is applied or vapor-deposited to form a coating (film) on the fitting contact portion between the molded body 1a and the jig 2a, which are product parts, so that the molded body 1a and the jig 2a are formed. Does not come into contact with each other, and maintains a stable state without being decomposed even when high heat is applied in the degreasing and sintering steps, so that the product 1 and the jig 2 obtained as a sintered body come into contact with each other. Never. It is generally said that a molded product as a product part is easily deformed in the sintering step when it has a shape with many irregularities. However, according to the present invention, a molded product with a product part with a large irregularity is cured. Since the shape is simplified by fitting and integrating with the tool, if the material components of the molded body 1a and the jig 2a are unified, deformation due to the difference in shrinkage of each part or the influence of the placement (deformation due to its own weight) Can be eliminated.

By making the material component of the jig 2a slightly binder-rich than that of the molded body 1a, the jig 2a has a higher shrinkage ratio until the sintering step, and the same effect as sizing can be obtained. . After sintering, the product 1 and the jig 2 obtained as a sintered body are separated, and a sintered body as the desired undeformed product 1 is obtained.

[0009]

Embodiment 1 FIGS. 6 and 7 show a manufacturing method of this embodiment. First, an injection molding machine 5 is touched to a mold 4a to perform injection molding of a jig 2a. At this time, on the surface of the jig 2a, since the ceramic is subsequently applied or vapor-deposited, the portion to be fitted to the product portion has a slightly larger dimension in view of the thickness of the ceramic coating. Thereafter, a film of the ceramic coating 3 is applied to a portion of the surface of the jig 2a taken out of the mold 4a to be the fitting portion, and the fitting portion with the product portion is finished to a desired product portion size. The jig 2a is then inserted into a mold 4b for molding the product part, the product part is insert-molded with the same material as the jig 2a, and the molded body 1a, which is the product part to be a product, and the jig 2a are integrated. Be transformed into Thereafter, the integrated molded body 1a and jig 2a taken out are subjected to a degreasing step and a sintering step, and then separated into a sintered molded body 1b and a jig 2 to obtain a desired product (the molded body which is a product part). To obtain a sintered body 1).

In the above-described embodiment, the jig 2a previously injection-molded is coated with the ceramic coating 3, and the fitting portion with the molded body 1a, which is a product part, is finished to the same dimensions as the product part. Then, this is insert-molded to obtain a product part (molded body) 1a having a desired dimension.
Also, by performing insert molding, it is possible to omit the operation of assembling the product part (molded body) 1a and the jig 2a. The ceramic film such as Al ₂ O ₃ (alumina) applied to the fitting portion between the product part (molded body) 1a and the jig 2a is not denatured by the heat (about 1350 ° C.) of the degreasing and sintering steps. Therefore, the product 1 and the jig 2 do not come into contact with each other, and the product portion 1a and the jig 2a shrink in the same manner. 1) can be obtained.

[0011]

[Embodiment 2] Fig. 8 shows a manufacturing method of the present embodiment. An injection molding machine 5 is mounted on a mold 4 for simultaneously injection molding (family taking) a molded body 1a and a jig 2a as product parts. By touching and performing injection molding, a molded body 1a and a jig 2a are obtained. At this time, the fitting portion of the jig 2a with the formed body 1a is formed to be larger than the formed body 1a by about 0.01 mm including the fitting clearance when the film of the ceramic coating 3 is applied. Thereafter, a ceramic coating 3 is applied to the surface of the jig 2a, and the molded body 1a is formed via a film.
a. Thereafter, degreasing is performed in the same manner as in Example 1 described above.
Separation is performed through a sintering process to obtain a desired product (sintered body) 1.

In the above-described embodiment, the compact 1a and the jig 2a are integrated with each other via the film of the ceramic coating 3, and degreased and sintered to form the compact 1b without sizing and deformation. It can be obtained in the same manner as in the first embodiment. In addition, by molding the molded body 1a and the jig 2a as a family and performing injection molding, the number of molds can be reduced to one, and a low-cost, non-deformed product can be obtained.

[0013]

Third Embodiment FIG. 9 shows a manufacturing method of this embodiment, similarly to Embodiment 1 and 2 described above, the step of injection molding the molded body and the jig, Al ₂ O ₃ on a jig And the like, a process of coating ceramics, a degreasing and sintering process, and a separation process. In the case of the molded body 1a which is a product part having a cross-sectional shape as shown in FIG. 9, a jig to be fitted with the molded body is divided into several parts (for example, 2a, 2c) and molded.
A film of a ceramic coating 3 such as Al ₂ O ₃ is applied to the mutual contact portions of the molds 2a and 2c and the contact portions of the jigs 2a and 2c and the molded body 1a, and the molded body 1a and the jigs 2a and 2c are assembled and integrated. . At this time, the dimensions of the jigs 2a and 2c are
The dimensions including the clearance are expected so that the ceramics 3 can be fitted to the molded body 1a even after the film is applied. After the integration, the product (sintered body) 1 and the jigs 2b and 2d are separated through a degreasing and sintering process to obtain a desired product.

In the above-described embodiment, when the product portion has the shape shown in FIG. 9 and has an undercut, the jig is divided into several parts (2a) as in this embodiment. 2c), the molded body 1a and the jig 2
By applying a film of the ceramic coating 3 to each of the contact portions a and 2c, it is possible to divide each of them even after degreasing and sintering. It is possible to obtain.

[0015]

Embodiment 4 FIG. 10 shows a process flow of the manufacturing method of this embodiment, in which a molded article as a product part and a jig are subjected to injection molding, and thereafter, the jig is subjected to a first degreasing. In the process, and in the contact part between the molded body and the jig that has gone through the degreasing process, Al
Ceramic coating such as ₂ O ₃ (alumina) is performed. After the degreasing of the jig is completed, the molded body is assembled and integrated, degreased again, and sintered. Thereafter, each is separated to obtain the desired product.

In this embodiment described above, the jig is first degreased, so that the total binder content when the jig and the molded body are integrated is small, and the organic binder after the first degreasing is performed. Since the residue, that is, the residue, is reduced, the sinterability is improved in addition to the same effects as those of the first, second, and third embodiments, and a higher quality product can be obtained.

[0017]

As described above, according to the wood invention, it is possible to manufacture a ceramic or metal powder sintered body which is not deformed by shrinkage or its own weight even in a complicated shape having no bearing surface. . In addition, by providing a film for preventing contact at the contact portion between the molded body and the jig, it becomes possible to divide each of them after sintering. In addition, by forming this film by applying or vapor-depositing physicochemically stable ceramics, there is no denaturation due to the heat of degreasing and sintering, and therefore, a ceramic or metal powder sintered body without deformation Becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view illustrating a manufacturing method according to the present invention.

FIG. 2 is a cross-sectional view illustrating a ceramic coating step in an example of the manufacturing method of the present invention.

FIG. 3 is a cross-sectional view showing a sintering step in an example of the manufacturing method of the present invention.

FIG. 4 is a cross-sectional view showing a product separation step in an example of the production method of the present invention.

FIG. 5 is an exemplary process chart of the manufacturing method of the present invention.

FIG. 6 is a process chart of the manufacturing method according to the first embodiment of the present invention.

FIG. 7 is an explanatory diagram of the manufacturing method in the example.

FIG. 8 is an explanatory diagram of a manufacturing method in Embodiment 2 of the present invention.

FIG. 9 is an explanatory diagram of a manufacturing method according to a third embodiment of the present invention.

FIG. 10 is a process chart of the manufacturing method according to the fourth embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 product 1a molded body 2 jig 2a jig 3 ceramic coating

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-70244 (JP, A) JP-A-3-236592 (JP, A) JP-A-4-259306 (JP, A) 232774 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C04B 35/64 B22F 3/10 F27D 3/12

Claims (2)

(57) [Claims] 1. A method of manufacturing a ceramic or metal powder sintered body, wherein a kneaded body of ceramic or metal powder and an organic binder is injection-molded as an injection molding material to obtain a molded body as a product part; A step of injection-molding a kneaded body of the same material or a kneaded body of the same material and having a large amount of an organic binder as an injection molding material, and obtaining a jig to be fitted and combined with the above-mentioned molded body; A step of applying a film for preventing the contact between the two, and a step of degrease and sintering the molded body and the jig fitted and combined via the film. A method for producing a ceramic or metal powder sintered body, characterized by comprising: 2. The method according to claim 1, wherein the step of applying the film is performed by applying or depositing physicochemically stable ceramic on a fitting contact portion between the molded body and the jig.
The method for producing a ceramic or metal powder sintered body according to the above.